In present day merchandising point-of-sale operations, data pertaining to the merchandised item purchased is obtained by reading data encoded indicia such as a bar code printed on the merchandised item. In order to standardize the bar codes used in various point-of-sale readout systems, the grocery industry has adopted a universal product code (UPC) which is in the form of a bar code. Various reader systems have been constructed to read this bar code including hand-held wands which are moved across the bar code and stationary optical reader systems normally located within the check-out counter and in which the merchandise item purchased is moved across a window constituting the scanning area of the counter, which movement is a part of the process of loading the item in a baggage cart.
The stationary scanning systems presently available utilize a rotating mirror for generating a scan pattern used in reading the bar code. Examples of this type of scanning system are found in U.S. Pat. Nos. 3,916,158, 3,995,166 and 4,057,784. Limitations of this type of scanner structure include tight mechanical requirements to provide the required registry of the scan pattern on the target area, which requirement limits the operating efficiency of such scanning apparatuses. In addition, this type of scanning apparatus by necessity is large in size and weight and therefore high in cost. It is therefore an object of this invention to provide an improved scanning apparatus for projecting a multiple-line scan pattern in a bar code reader apparatus. It is a further object of this invention to provide a scanning apparatus which has few operating parts and therefore is low in cost but yet highly reliable. It is still another object of this invention to provide an improved scanning apparatus which generates a multiple-line scan pattern which provides a high rate of good readings of bar code indicia not orientated in a position perpendicular to the scanning beam.